added elision filter

defined article word maps for french, italian, irish and catalan
defined elision filters for these same languages
updated analyers for french and italian to use this new filter
irish and catalan still depend on other missing pieces
closes #25

analysis/token_filters/elision_filter/articles_ca.go

@@ -0,0 +1,13 @@
+package elision_filter
+
+// this content was obtained from:
+// lucene-4.7.2/analysis/common/src/resources/org/apache/lucene/analysis
+
+var CatalanArticles = []byte(`
+d
+l
+m
+n
+s
+t
+`)

analysis/token_filters/elision_filter/articles_fr.go

@@ -0,0 +1,20 @@
+package elision_filter
+
+// this content was obtained from:
+// lucene-4.7.2/analysis/common/src/resources/org/apache/lucene/analysis
+
+var FrenchArticles = []byte(`
+l
+m
+t
+qu
+n
+s
+j
+d
+c
+jusqu
+quoiqu
+lorsqu
+puisqu
+`)

analysis/token_filters/elision_filter/articles_ga.go

@@ -0,0 +1,10 @@
+package elision_filter
+
+// this content was obtained from:
+// lucene-4.7.2/analysis/common/src/resources/org/apache/lucene/analysis
+
+var IrishArticles = []byte(`
+d
+m
+b
+`)

analysis/token_filters/elision_filter/articles_it.go

@@ -0,0 +1,28 @@
+package elision_filter
+
+// this content was obtained from:
+// lucene-4.7.2/analysis/common/src/resources/org/apache/lucene/analysis
+
+var ItalianArticles = []byte(`
+c
+l
+all
+dall
+dell
+nell
+sull
+coll
+pell
+gl
+agl
+dagl
+degl
+negl
+sugl
+un
+m
+t
+s
+v
+d
+`)

analysis/token_filters/elision_filter/elision_filter.go

@@ -0,0 +1,50 @@
+//  Copyright (c) 2014 Couchbase, Inc.
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+//  except in compliance with the License. You may obtain a copy of the License at
+//    http://www.apache.org/licenses/LICENSE-2.0
+//  Unless required by applicable law or agreed to in writing, software distributed under the
+//  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+//  either express or implied. See the License for the specific language governing permissions
+//  and limitations under the License.
+package elision_filter
+
+import (
+	"bytes"
+
+	"github.com/couchbaselabs/bleve/analysis"
+)
+
+const RIGHT_SINGLE_QUOTATION_MARK = "’"
+const APOSTROPHE = "'"
+
+const APOSTROPHES = APOSTROPHE + RIGHT_SINGLE_QUOTATION_MARK
+
+type ElisionFilter struct {
+	articles analysis.WordMap
+}
+
+func NewElisionFilter(articles analysis.WordMap) *ElisionFilter {
+	return &ElisionFilter{
+		articles: articles,
+	}
+}
+
+func (s *ElisionFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	rv := make(analysis.TokenStream, 0)
+
+	for _, token := range input {
+		firstApostrophe := bytes.IndexAny(token.Term, APOSTROPHES)
+		if firstApostrophe >= 0 {
+			// found an apostrophe
+			prefix := token.Term[0:firstApostrophe]
+			// see if the prefix matches one of the articles
+			_, articleMatch := s.articles[string(prefix)]
+			if articleMatch {
+				token.Term = token.Term[firstApostrophe+1:]
+			}
+		}
+		rv = append(rv, token)
+	}
+
+	return rv
+}

analysis/token_filters/elision_filter/elision_filter_test.go

@@ -0,0 +1,116 @@
+//  Copyright (c) 2014 Couchbase, Inc.
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+//  except in compliance with the License. You may obtain a copy of the License at
+//    http://www.apache.org/licenses/LICENSE-2.0
+//  Unless required by applicable law or agreed to in writing, software distributed under the
+//  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+//  either express or implied. See the License for the specific language governing permissions
+//  and limitations under the License.
+package elision_filter
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/couchbaselabs/bleve/analysis"
+)
+
+func TestElisionFilter(t *testing.T) {
+
+	frenchArticlesMap := analysis.NewWordMap()
+	err := frenchArticlesMap.LoadBytes(FrenchArticles)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	italianArticlesMap := analysis.NewWordMap()
+	err = italianArticlesMap.LoadBytes(ItalianArticles)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	catalanArticlesMap := analysis.NewWordMap()
+	err = catalanArticlesMap.LoadBytes(CatalanArticles)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	irishArticlesMap := analysis.NewWordMap()
+	err = irishArticlesMap.LoadBytes(IrishArticles)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tests := []struct {
+		articleMap analysis.WordMap
+		input      analysis.TokenStream
+		output     analysis.TokenStream
+	}{
+		{
+			articleMap: frenchArticlesMap,
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("l'avion"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("avion"),
+				},
+			},
+		},
+		{
+			articleMap: italianArticlesMap,
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("dell'Italia"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Italia"),
+				},
+			},
+		},
+		{
+			articleMap: catalanArticlesMap,
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("l'Institut"),
+				},
+				&analysis.Token{
+					Term: []byte("d'Estudis"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Institut"),
+				},
+				&analysis.Token{
+					Term: []byte("Estudis"),
+				},
+			},
+		},
+		{
+			articleMap: irishArticlesMap,
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("b'fhearr"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("fhearr"),
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		elisionFilter := NewElisionFilter(test.articleMap)
+		actual := elisionFilter.Filter(test.input)
+		if !reflect.DeepEqual(actual, test.output) {
+			t.Errorf("expected %s, got %s", test.output[0].Term, actual[0].Term)
+		}
+	}
+}

config.go

@@ -24,6 +24,7 @@ import (
 	"github.com/couchbaselabs/bleve/analysis/tokenizers/unicode_word_boundary"
 
 	"github.com/couchbaselabs/bleve/analysis/token_filters/cld2"
+	"github.com/couchbaselabs/bleve/analysis/token_filters/elision_filter"
 	"github.com/couchbaselabs/bleve/analysis/token_filters/length_filter"
 	"github.com/couchbaselabs/bleve/analysis/token_filters/lower_case_filter"
 	"github.com/couchbaselabs/bleve/analysis/token_filters/stemmer_filter"
@@ -153,6 +154,12 @@ func init() {
 	Config.Analysis.TokenMaps["ckb_stop"] = Config.MustLoadStopWords(stop_words_filter.SoraniStopWords)
 	Config.Analysis.TokenMaps["th_stop"] = Config.MustLoadStopWords(stop_words_filter.ThaiStopWords)
 
+	// register article token maps for elision filters
+	Config.Analysis.TokenMaps["fr_articles"] = Config.MustLoadStopWords(elision_filter.FrenchArticles)
+	Config.Analysis.TokenMaps["it_articles"] = Config.MustLoadStopWords(elision_filter.ItalianArticles)
+	Config.Analysis.TokenMaps["ca_articles"] = Config.MustLoadStopWords(elision_filter.CatalanArticles)
+	Config.Analysis.TokenMaps["ga_articles"] = Config.MustLoadStopWords(elision_filter.IrishArticles)
+
 	// register char filters
 	htmlCharFilterRegexp := regexp.MustCompile(`</?[!\w]+((\s+\w+(\s*=\s*(?:".*?"|'.*?'|[^'">\s]+))?)+\s*|\s*)/?>`)
 	htmlCharFilter := regexp_char_filter.NewRegexpCharFilter(htmlCharFilterRegexp, []byte{' '})
@@ -187,6 +194,7 @@ func init() {
 	Config.Analysis.TokenFilters["stemmer_sv"] = stemmer_filter.MustNewStemmerFilter("swedish")
 	Config.Analysis.TokenFilters["stemmer_tr"] = stemmer_filter.MustNewStemmerFilter("turkish")
 
+	// register stop token filters
 	Config.Analysis.TokenFilters["stop_token_da"] = stop_words_filter.NewStopWordsFilter(
 		Config.Analysis.TokenMaps["da_stop"])
 	Config.Analysis.TokenFilters["stop_token_nl"] = stop_words_filter.NewStopWordsFilter(
@@ -244,6 +252,16 @@ func init() {
 	Config.Analysis.TokenFilters["stop_token_th"] = stop_words_filter.NewStopWordsFilter(
 		Config.Analysis.TokenMaps["th_stop"])
 
+	// register elision filters
+	Config.Analysis.TokenFilters["elision_fr"] = elision_filter.NewElisionFilter(
+		Config.Analysis.TokenMaps["fr_articles"])
+	Config.Analysis.TokenFilters["elision_it"] = elision_filter.NewElisionFilter(
+		Config.Analysis.TokenMaps["it_articles"])
+	Config.Analysis.TokenFilters["elision_ca"] = elision_filter.NewElisionFilter(
+		Config.Analysis.TokenMaps["ca_articles"])
+	Config.Analysis.TokenFilters["elision_ga"] = elision_filter.NewElisionFilter(
+		Config.Analysis.TokenMaps["ga_articles"])
+
 	// register analyzers
 	keywordAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "single", []string{})
 	Config.Analysis.Analyzers["keyword"] = keywordAnalyzer
@@ -263,13 +281,13 @@ func init() {
 	Config.Analysis.Analyzers["en"] = englishAnalyzer
 	finnishAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_fi", "stemmer_fi"})
 	Config.Analysis.Analyzers["fi"] = finnishAnalyzer
-	frenchAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_fr", "stemmer_fr"})
+	frenchAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"elision_fr", "to_lower", "stop_token_fr", "stemmer_fr"})
 	Config.Analysis.Analyzers["fr"] = frenchAnalyzer
 	germanAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_de", "stemmer_de"})
 	Config.Analysis.Analyzers["de"] = germanAnalyzer
 	hungarianAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_hu", "stemmer_hu"})
 	Config.Analysis.Analyzers["hu"] = hungarianAnalyzer
-	italianAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_it", "stemmer_it"})
+	italianAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"elision_it", "to_lower", "stop_token_it", "stemmer_it"})
 	Config.Analysis.Analyzers["it"] = italianAnalyzer
 	norwegianAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_no", "stemmer_no"})
 	Config.Analysis.Analyzers["no"] = norwegianAnalyzer